Ratchet wrenches and tools including those of the type which have a socket-locking and quick-release mechanism have been long established in the relevant art. Many and varied types of such mechanisms for ratchet and drive reversing ratchet wrenches have been described in the literature, and mechanisms have been incorporated in commercial ratchet drives sold for use by mechanics. Many of the prior art structures depend upon and invoke substantially the same mechanical principles, each being engineered for use in ratchet drive wrenches in which drive reversal of the wrench is effected by impressing a rotational force on a lever or upon an arcuately-shiftable plate to change the operational orientation of an indexing element. The latter is conveniently a toothed pawl, the teeth of which intercouple or interlock with cooperating teeth formed in a driving collar or ring of the tool head. In such ratcheting devices, counter-rotation of the tool handle effects disengagement of the ratchet teeth to permit the drive handle to be shifted in the opposite direction for subsequent forward reactivation and drive.
Typically, in ratchet drive wrenches of the type referred to, the pawl is caused to shift between two opposed positions in which the toothed ends of the pawl engage, sequentially, at annularly-spaced positions within an encircling toothed drive ring or collar of the tool head, each such shift being correlated with either clockwise or counter-clockwise torque-transmitting engagement between the driving ring or collar and a driven, coaxial body or core coupled to the collar. Conveniently, the core carries a shank, stud or boss for securement of a tool element thereto.
A ratchet wrench which includes the features referred to above is described in Chow U.S. Pat. No. 4,512,218, and the entire disclosure of that patent is hereby specifically incorporated herein by reference to the extent it is not inconsistent herewith.
While the structures of the prior art are suitable for securing and for effecting release of stud-carried, selectable driving tool elements such as sockets in ratchet drive tools of the broad class described, the mechanical arrangements and the specific physical form of the release mechanisms of the prior art cannot be used in a ratchet drive in which the direction reversing indexing mechanism is shifted between each of its two opposed rotational modes through the application of digital pressure on a finger-contact element which projects above a top face of the wrench head and which does not require the application of a rotational force. That is, the reversing indexing mechanism in wrenches in which the present invention finds utility is actuated through force applied such as to produce a component projecting axially into the face of the tool head. The structure described obviates any need to grasp a bar-like key or a ring to rotate the same in the tool head. Such a ratchet drive wrench is shown in K. K. Chow, U.S. Pat. No. 4,280,379, and the entire disclosure of that patent is hereby incorporated by reference to the extent it is not inconsistent herewith.